Optical branching device with internal waveguide

Abstract

An optical waveguide device of the invention has an optical waveguide which is a region formed in a transparent substrate and has a refractive index higher than that of the transparent substrate. The optical waveguide consists of first and second optical waveguide elements each having one end exposed to a surface of the transparent substrate and the other end connected in the vinicity of the surface of the transparent substrate, such that the connecting portion thereof is exposed to the surface of the transparent substrate.

What is claimed is: 
     
       1. An optical waveguide device comprising a region formed in a transparent substrate, the region having a refractive index higher than a refractive index of the transparent substrate and defining an optical waveguide within the transparent substrate, said optical waveguide having first and second optical waveguide elements, each of the waveguide elements having one end connected to the one end of the other optical waveguide element in a substantially V-shape in the vicinity of a first surface of said transparent substrate, a connecting portion of the connected ends of the two optical waveguide elements being exposed to the first surface of said transparent substrate, and a remaining end exposed to a surface of the transparent substrate other than said first surface; and a third optical waveguide element having one end exposed to the first surface of said transparent substrate, a remaining end of said third optical waveguide element and the remaining end of said second optical waveguide element being connected in a substantially V-shape in the vicinity of a second surface of said transparent substrate, and a connecting portion of the connected remaining end of said third optical waveguide element and the remaining end of said second optical waveguide element being exposed to the second surface of said transparent substrate.   
     
     
       2. An optical waveguide device according to claim 1, wherein said optical waveguide further has a fourth optical waveguide element having one end exposed to the second surface of said transparent substrate, the other end of said fourth optical waveguide element and the one end of said third optical waveguide element being connected in a substantially V shape in the vicinity of the first surface of said transparent substrate, and a connecting portion thereof being exposed to the first surface of said transparent substrate. 
     
     
       3. An optical waveguide device comprising a region formed in a transparent substrate, the region having a refractive index higher than a refractive index of the transparent substrate and defining an optical waveguide within the transparent substrate, said optical waveguide having first and second optical waveguide elements, each of the waveguide elements having one end connected to the one end of the other optical waveguide element in a substantially V-shape in the vicinity of a first surface of said transparent substrate, a connecting portion of the connected ends of the two optical waveguide elements being exposed to the first surface of said transparent substrate; and wherein an axis of each of said optical waveguide elements lies within an imaginary plane perpendicular to the first surface of said transparent substrate and is inclined at the same angle with respect to a line normal to the first surface of said transparent substrate, and the axes of the first and second optical waveguide elements also intersecting one another at the surface of the transparent substrate where the connecting portion is exposed;   wherein an optical filter is arranged on each surface portion of said transparent substrate where the connecting portion is exposed; and   wherein the optical filter transmits light of predetermined wavelengths and reflects light of other wavelengths, respectively.   
     
     
       4. An optical waveguide device according to claim 3, wherein each optical filter transmits light in predetermined amounts and reflects remaining light, respectively. 
     
     
       5. An optical waveguide device according to claim 3, wherein another optical filter is arranged at an unconnected end of one of said optical waveguide elements. 
     
     
       6. An optical waveguide device according to claim 3, wherein one connecting portion in said transparent substrate and one end of an optical waveguide in a second transparent substrate are opposed to each other. 
     
     
       7. An optical waveguide device comprising a region formed in a transparent substrate and having a refractive index higher than a refractive index of the transparent substrate for defining an optical waveguide within the transparent substrate, said optical waveguide having first and second optical waveguide elements, each element having one end connected to the one end of the other element in a substantially V-shape in the vicinity of a first surface of said transparent substrate, a connecting portion of the connected ends of said first and second optical waveguide elements being exposed to the first surface of said transparent substrate, and a remaining end of each of the first and second optical waveguide elements being exposed to a surface of the transparent substrate other than said first surface; and a second transparent substrate including a region within the second transparent substrate having a refractive index higher than the refractive index of said second transparent substrate defining a second continuous, monolithic optical waveguide in the second transparent substrate, said second optical waveguide having first and second optical waveguide elements, each element having one end connected to one end of the other optical waveguide element in a substantially V-shape in the vicinity of a first surface of said second transparent substrate, a connecting portion of the connected ends of the first and second optical waveguide elements of the second transparent substrate being exposed to the first surface of said second transparent substrate, and a remaining end of each of said first and second optical waveguide elements of the second transparent substrate being exposed to a surface of the second transparent substrate other than said first surface of said second transparent substrate, the two transparent substrates being positioned with the first surfaces of each transparent substrate and with the connecting portions exposed to the first surfaces of each transparent substrate in opposition; and   a liquid crystal between the first surfaces and the connecting portions of the two transparent substrates in opposition.   
     
     
       8. An optical waveguide device according to claim 7, wherein each surface of said transparent substrate and each surface of said second transparent substrate at which a remaining end of an optical waveguide element is exposed is formed substantially perpendicularly to an optical axis of said optical waveguide element exposed at said surface. 
     
     
       9. An optical waveguide device comprising a region formed in a transparent substrate and having a refractive index higher than a refractive index of the transparent substrate for defining an optical waveguide within the transparent substrate, said optical waveguide having first and second optical waveguide elements, each element having one end connected to the one end of the other element in a substantially V-shape in the vicinity of a first surface of said transparent substrate, a connecting portion of the connected ends of said first and second optical waveguide substrate, and a remaining end of each of the first and second optical waveguide elements being exposed to a surface of the transparent substrate other than said first surface; and a third optical waveguide element within the transparent substrate formed to branch from said second optical waveguide element at a midpoint between the two ends of said second optical waveguide element forming an acute angle towards the connecting portion with respect to said second optical waveguide element;   a portion of light transmitted through said first optical waveguide element passing through an optical filter arranged at a portion of the first surface of said transparent substrate where said connecting portion is exposed, a remaining portion of light being reflected by said optical filter through the second waveguide element; and   light input through said third optical waveguide element merging with said remaining portion of light transmitted through said second optical waveguide element.   
     
     
       10. An optical waveguide device according to claim 9, wherein said first and second optical waveguide elements are respectively linear in shape. 
     
     
       11. An optical waveguide device according to claim 10, wherein each surface of said transparent substrate at which the remaining end of one of said first and second optical waveguide elements is exposed is formed substantially perpendicularly to an optical axis of the one of said first and second optical waveguide elements exposed at the surface. 
     
     
       12. An optical waveguide device according to claim 9, wherein said first and second optical waveguide elements each has an arcuated portion between the connecting portion and the remaining end thereof, and an optical axis at the remaining end is substantially perpendicular to a surface of said transparent substrate at which said remaining end of the optical waveguide element is exposed.